I bought a 1968 mustang coupe from a guy in California that said it was a GT. Now I am trying to sell it and the guy that wants to buy it said it's not a GT. How do I know if it is a true GT and not a clone?? It has a 289 with a holley 4 bbl and C-4 transmission. Other than that, I don't know what else to look for. Thanks for any help you can give me.